Electrically operated distantcontrol device



oct. 1, 1946. A. mm f 2,408,543

ELEGTRICALLY OPERATED DISTANT-CONTRQL DEVICE' 'Filed Deo; 16, 1942 2 Shef-:ts-Sheet 1 Oct. 1, 1946.

A. ARNOT ELECTRICALLY OPERTED-DISTANT-CONTROL DEVICE Filed Dec. 16, 1942 2 Sheets-Sheet 2 Patented Oct. 1, 1946 ELECTRICALLY OPERATED DISTANT- CONTROL DEVICE Alfred Arnot, Warrington, England, assignor to Aeronautical & Mechanical Investments Limited, a British company Application December 16, 1942, Serial No. 469,270 In Great Britain September 22, 1941 1 Claim. 1

This invention comprises improvements in or relating to electrically operated distant-control devices.

It is an object ofthe invention t provide a device whereby a control member in one position has its movement followed by a follower member in another position, the synchronisation of the movements being effected electrically.

According to the present invention a transmitter is provided comprising a control member and two make-and-break contacts so operatively connected to the control member that one of them is closed repeatedly when the control member is moved in one direction and the other contact is closed repeatedly when the control member is moved in the other direction, the interconnection between the control member and the contacts being such that the number of operations depends upon the extent of the control members movement, in combination with two control lines, one of which receives impulses through one of the make-and-break contacts and the other through the other contact and a receiver comprising two electromagnetic actuating mechanisms for pawl-and-ratchet movement, one connected to one control line and the other to the other line one of which serves to actuate a follower member in one direction and the other to actuate it in the opposite direction. By this means if the actuating member is moved in one direction the rnake-and-breakl contact which is repeatedly closed on this direction of movement energises one of the control lines and thereby operates one of the electromagnetic ratchet devices to move the follower member in a corresponding direction through a number of steps corresponding to the extent of the movement of the actuating member. When the actuating member is moved in the opposite direction the other control line is energised periodically and the follower member is caused to make a corresponding number of steps in the opposite direction. Thus the follower member will follow the control member with an accuracy which is only limited by the nneness of the steps of its movement.

The make-and-break contacts may be directly mechanically operated by a cam device ordevices driven by the control member. Alternatively the make-and-break contacts may be actuated by a relay the circuit of which is closed by a cam or equivalent part moved by the control member and opened again when synchronism between the control member and the follower is reached by means of electromagnetically op- 2 erated ratchet mechanism connected to the control lines.

Preferably in order to facilitate the use of fine steps and of a small amount of energy in the transmission lines the pari-I which is to be controlled is not directly mechanically operated by the pawl-and-ratchet devices but is caused to copy closely the movements imparted by the pawl-and-ratchet devices through the interposition of an electric servo mechanism as hereinafter described.

The following is a description, by way of example, of certain forms of apparatus in accordance with the invention,` but it will be understood that this apparatus is described only to indicate the principle of the operation and many modiflcations can be made in detail without departing from the spirit of the invention.

In the accompanying drawings:

Figure l is a diagram of one form of distantcontrol apparatus in accordance with the invention,

Figure 2 is a diagram of a modification of Figure 1, and

Figure 3 is a diagram of an alternative form of apparatus.

Referring first to Figure 1, a control member II is provided in the form of an arm mounted on a rotatable shaft I2. The shaft carries a large gear-wheel I3 which meshes with a pinion I4 on a secondary shaft I5 which carries a multipoint cam I6. The points I'I of the cam are arranged to strike in succession upon a striker I8 which forms part of a spring contact-arm I9 disposed radially to the cam with the striker I8 lying in the path of the points Il. When the cam IE is rotated clockwise by the control member I l, the spring contact-arm I9 is repeatedly deflected to the left of its mid position as viewed in the figure, and makes and breaks contact repeatedly with an electric contact 20 located to the left of it. When the control member II is moved in the other direction, the cam I6 is rotated anti-clockwise and the arm I9 is deflected repeatedly towards another contact 2I located on the other side of it from the contact 2l). It will be observed that the number of times which contact is made in either direction of rotation depends upon the extent of the movement of the control member.

From the two contacts 20, 2I there extend two control lines 22, 23 to a receiving apparatus which is indicated generally in the drawings by the numeral 24. The spring contact-arm I9 is connected by a line25 to one pole of a battery 3 28 and the other pole of the battery is connected to a return line 21.

The receiver 24 comprises two electromagnets 2B, 29 energised by the control-lines 22, 23, respectively. Each electromagnet has a pivoted armature 3i) which carries a pawl 3 I, and a spring 32 in each case serves to return the armatures 30 to their initial position when the magnets 28 or 29 are de-energised. The pawls 3| are located one on each side of a ratchet-wheel 33 having double-faced teeth so that one pawl will rotate the ratchet in one direction and the other in the other direction. The pawls 3| also have pallet faces 34 which, when they are drawn back :by the spring 32, engage fixed pins 35 which lift them out of engagement with the ratchet-teeth. Thus, for each energization of either of the electromagnets 28, 29, one of the pawls 3| is drawn down, engages the ratchet-wheel 33 and moves it forward one tooth; when the current is interrupted the pawl returns to its initial position and the pallet engages the pin 35 and thus lifts the pawl away from the ratchet so that it does not interfere with the movement of the ratchet by the other pawl should the next impulse come in on the other transmission line.

The ratchet-wheel 33 is also engaged by a spring centering member 36 which bears on the notches between the ratchet-teeth, or on a separate series of centering recesses, and which serves to prevent the ratchet wheel from overrunning so as to move more than one tooth at each impulse. Any other means for preventing overrunning may be employed if desired, such means being well known.

The ratchet-Wheel 33 is mounted on a secondary shaft 31 which is geared to a main shaft 38 by means of a pinion 33 on the secondary shaft 31 and a gear-wheel 4|) on the main shaft 3B. The ratio of the gear-wheel 4|] to the pinion 33 multiplied by the number of ratchet teeth on tc wheel 33 is equal to the ratio of gear-wheel I3 to pinion I4 multiplied by the number of points I1 of the cam I6, and thus the main shaft 33 will rotate angularly to the same extent and in the same direction as any movement applied -b-y the control member I I to the gear-wheel I3, assuming the connections are appropriately made. (The gear ratio in the transmitter and the receiver 24 may diifer if desired in cases where the angular movement of the receiver is not required to be identical but to bear some ratio to that of the transmitter.)

The part which is to be controlled, which might be, say, the flaps on the wing of an aircraft, is provided with a control shaft 4| which constitutes a follower member and which is concentric with the main shaft 38 of the receiver. The two shafts are brought close together without being mechanically interconnected. On the main shaft 38 is a cam 42 having a bulge 43 on one side which extends around part of its circumference. Close to the cam there is mounted on the follower shaft 4I a, control disc 44 carrying two insulated spring contact-arms 45, 45 which are electrically connected together and form the movable members of a two-way contact circuit. Each arm carries a Contact 41 which is adapted to close against one of two spring contact-arms 48, 49 connected respectively to the two lines 55, I of a two-way circuit. The ends 52, 53 of the contact-arms 45, 45 are curved inwardly to engage the cam 43 on the main shaft 38 and their ends engage simultaneously the ends of the bulge on the cam in such manner that if the cam moves relatively i' act as signal lines.

to the disc 44 clockwise, as viewed in the ligure, it will lift the contact-arm 45 and close the circuit to the line wire 5|, while if it moves antlclockwise relatively to the disc 44, it will lift the Contact arm. 46 and close the line-wire 5B. The contact-arms 45, 46 are energised by a line 54 which is branched from the line 21, hereinbefore referred to, connected to the battery 26.

The lines 50 and 5I are connected to the terminals 55, 51 of a reversible electric motor 55. The motor 55 has a third terminal 58 which is connected to a return-line 59 leading to the other terminal of the battery 25 from that to which the line 54 is connected. The motor is such that if the line 50 is energised, it will rotate in one direction, and if the line 5I is energised, it will rotate in the other direction. The motor is connected mechanically to the follower-shaft 4| 'through an electromagnetic clutch Bil, a worm Gl and worm-wheel 62, the arrangement being such that if the contact-arm 45 is lifted vby the main shaft 38 moving clockwise, the followershaft 4I will be driven clockwise until the disc 44 brings the end 52 of the contact-arm 45 past the end of the bulge 43, whereupon the circuit is broken and motion ceases, while if the main shaft 38 is driven in the opposite direction, the contact on the arm 45 will be closed, the line 53 will be energised, and the motor will rotate in the reverse direction causing the follower-shaft 4| to move anti-clockwise until it catches up with the cam 43 and the circuit is broken again.

In result, the follower-shaft 4I, which is also the control shaft for the wing-flaps or other device to be operated is made to conform to thc movements of the main shaft 38, which follows the movements of the control-member and thus the nap or other device to be operated is made to conform precisely to the movements of the control-member II, without any mechanical connection existing between the parts and without the transmission from the transmitter to the receiver 24 being required to convey the energy for operating the parts; the lines 22, 23 merely It will of course be understood that instead of the control-member II and the main shaft 38 and follower-shaft 4| being employed, equivalent parts moving in straight lines instead of angular-ly could be used.

In any mechanism of this kind it is desirable to provide means to ensure that in the event of loss of synchronism between the transmitter and the receiver, synchronism can be restored simply. To this end, in the mechanism described, a number of teeth are cut out of the gear-wheel 4|)y as shown at 55 in the position which corresponds to the extreme of the movement of the controlmember I, where the latter abuts against a stop GE. A normally-closed push-button 61 is provided in one of the transmission lines (the line 22 in the figure), so that the line can be broken by operating the push-button whenever desired. If this is done and the control-member I is moved, movement of the ratchet-wheel 33 will take place s in a clockwise direction only, because the electromagnet 28 which would rotate it in an anticlockwise direction is prevented from operating by the line 23 being broken. Thus on@J or two partial reciprocations of the control-member I| will move the gear-wheel 4U to its extreme position when the gap 65 comes opposite the pinion 39 and the parts are no longer in gear; hence it will move no further. The control-member II being then moved to the corresponding extreme position against the stop B6, the push-button 51 merely to move the shaft |4| and disc |44 and does not directly operate a cam such as the cam I6 in Figure 1. The movement of the control member can therefore be made extremely light and it can, if desired, be provided with a friction control such as to give a suitable feel to the movement.

In the event of synchronism being lost due to one of the pawls 3| or 3| slipping on a ratchet, synchronisation can be eifected by moving the control member to either eXtreme position. To this end, the gear-wheel |40 is provided with a notch |65 similar to the notch 65 in Figure 3, and at the extreme position of the control member |62 are disposed two spring loaded stops |55 and |56 so arranged that the pinion |39 just enters the notch |65 of the gear-wheel |40 when the control member |52 touches either of these stops |55 or |56l rlhe gear wheels |40 and 4D are also tted with bias springs such that at either eX- treme position of travel they tend to mesh with their respective pinions |39 or 39. If then the control member |62 be pressed against either of the spring loaded stops |55 or |56 the contacts |45, |43 or |46, |49 will be closed and the relay 20| or 20D willl vibrate and send impulses to the magnets |28, 26 or |29, 29.

This will rotate ratchet wheels |33 and 33 until the pinions |35 and 39 come to the cut away portions |65 and G5 of the gear-wheels |40 and 4U respectively; due to the fact that pinion |39 can then no longer rotate the gear-wheel |46, the cam |42 cannot rotate sufliciently far to open the contacts |45` |42 or |46, |49, as the control member |62 is being moved further than its normal travel by pressingT against the spring loaded stops |55 or |56, and in a short space of time both receiver and transmitter elements will have taken up their corresponding extreme positions, As soon as the control member |52 is released it will be pushed by the spring loaded stops to its own limiting position, whereupon the contacts |45, |43 or |45, |49 will ce opened and synchronism will have been restored.

It will be appreciated that the relays 2GB, 20|

should be given such natural frequency of operation by appropriate design of the parts as to make them work at the optimum speed for the ratchet mechanisms, and that this speed is quite independent of the speed at which the control- L,

member |52 is moved by the operator to a desired position. Moreover, more than one transmitter may be connected to the receiver by means of branch circuits from the control lines, and any transmitter will be able to effect movement of i the receiver from any desired position in the circuit. In this case means must be provided to ensure that the control-arms |62 of the various transmitters are all moved into the same position in response to movement of any one of them. This can be effected by connecting the shafts |38 to the shafts |4| by some form of clutching device which will transmit power from the shaft |38 to the shaft |4| whenever they are out of synchronism, but will not transmit power in the opposite direction. For example, an electric clutch can be provided between the two shafts electrically connected to the other transmitter or transmitters in such a way that movement of any one transmitter lever will energise the clutches of all the other transmitters. Again, each of the transmitters might be provided with a motor such as the motor 55, and the corresponding worm-gear G i, 132, but with means to disconnect it whenever it is desired to operate the shaft |4| by hand,

Instead of employing in the receiver or transmitter or both a ratchet-wheel with double-faced teeth and two sets of pawls. it is possible to employ two single ratchets which are connected together through a diierential gear, so that one ratchet drives the mechanism in one direction and the other in the other direction; in this case a convenient form of step by step ratchet mechanism is that commonly employed for operating preselector switches in automatic telephony,

I claim:

Electrically-operated distant-control apparatus .ha 'ing in combination, in a transmitter, a movable control member, a follower therefor, a cam and cam-engaging member carried one by the control member and the other by the follower, the cam having a contact-operating portion which when the follower is in synchronism with the control member is in close proximity to the cam-engaging member, idle sections of the cam adjoining said contact-operating portion, two pairs of make-and-break contacts operated by the cam-engaging member so that one pair of contacts is altered when the control member moves relatively to its follower from a position of synchronism therewith in one direction and the other pair when it moves in the other direction, two ratchet-operating repeating-relays the energizing circuits of which are controlled one by one of the said pairs of contacts and the other by the other pair line contacts repeatedly actuated by the relays when energized for making and breaking line circuits and thereby sending out repeated line signals, electromagnetically operated ratchet mechanism at the transmitter energized by said line signals and operatively connected to the follower to move it after the control member, at least one of the ratchet mechanisms comprising oppositely-handed ratchet teeth on a single shaft engaged by pawls, one pawl for moving the shaft in one direction and the other pawl for moving the shaft in the other direction and wherein the shaft is connected to the means for operating the contacts through a reduction gear so that the number of steps executed by the ratchet-operating relays in bringing the follower to its desired position is increased, said reduction gear comprising a gap for the purpose of automaticaliy synchronizing the transmitter and receiver at the extreme oi' movement of the parts in one direction or the other, and, in a receiver, similar magnetically operated ratchet mechanism operated in step with that of the transmitter by the same line signals to actuate a part to be controlled.

ALFRED ARNOT. 

